Fluid dispenser control system

ABSTRACT

A system for use with a fluid dispensing apparatus having a fluid flow metering mechanism and a nozzle including an automatic pressure differential-actuated full tank shutoff. The system comprises a holding tank, means for maintaining the pressure in the tank at a differential with respect to atmospheric pressure and for connecting the holding tank to the nozzle to actuate the shutoff, and a mechanical selector operatively linked to the metering sustem and to the first mentioned means for actuating those means when substantially a predetermined amount of fluid has been dispensed through the nozzle.

United States Patent [191 Healy [451 July 16,1974

[ FLUID DISPENSER CONTROL SYSTEM Primary Examiner-Robert B. Reeves [75]Inventor. James W. Healy, Wakefield, Mass. Assistant Examiner joseph J.Rona I Asslgneel Automatic y Waltham, Attorney, Agent, or Firm-Gordon R.Williamson, Esq.

Mass. 22 Filed: June 13, 1973 L f f f g g I system or use wit a wrspensmg apparatus [21] Appl' 369460 having a fluid flow meteringmechanism and a nozzle including an automatic pressuredifferential-actuated 52 us. 01 141/198, 222/20, 222/33 full tankshuteff- The System comprises a holding tank, [51] Int. Cl B65b l/30means for maintaining the Pressure in the tank in a 58 Field of Search222/14 23, differential with respect to atmospheric Pressure and2112/3144 57; 194 5 13; 141 192 229 for connecting the holding tank tothe nozzle to actuate the shutoff, and a mechanical selector operatively[5 References Ci d linked to the metering sustem and to the first men-UNITED STATES PATENTS tioned means for actuating those means whensubstan- 2 080 535 5/1937 D ZZZ/l4 tially a predetermined amount offluid has been dis- 2:906:30 9/1959 pensed through the nozzle. 3,005,47610/1961 Klaus 141/225 20 Claims, 6 Drawing Figures PAIENI JUL 1 61974SHEET 3 BF 4 FIG. 4

FIG. 5

PATENTED JUL'] 81974 saw a nr 4 Om mm mm FLUID DISPENSER CONTROL SYSTEMBACKGROUND OF THE INVENTION This invention relates to an automatic fluidflow shutoff system. The system is particularly suitable for use withgasoline pumps.

Presently, most gasoline stations dispense gasoline through conventionalpumps having mechanical computers which meter flow and indicate thedollar and cents amount of gasoline pumped, as well as nozzles whichincorporatevacuum actuated, full tank shutoff valves. Thus, an attendantcan latch an automatic hose nozzle shutoff topermit the flow of gasolineknowing that when a full tank condition exists in the car beingserviced, the flow of gasoline will automatically be interrupted. This,of course, allows the attendant to be free for checking oil andbatteries and attending to other operations while the tank is filling.

On many occasions,however, a customer orders less than the amount of gasthat is required to fill the vehicle gasoline tank. Usually such ordersare given in dollar amounts such as $1, $2 or more dollars. In suchcases, it is common for the gasoline attendant to manually operate thenozzle valve until the dollar amount is pumped. It has long beenrecognized that an automatic device for interrupting gasoline flow at apredetermined dollar or gallon amount prior to filling of the tank wouldbe highly desirable and useful to allow the gasoline attendant toservice a plurality of vehicles and- /or provide auxiliary services to asingle vehicle while gasoline is being pumped. e

In fact, many attempts to provide a predetermined dollar volumeautomatic gasoline pump shutoff have been made. In most cases, suchproposed constructions have been extremely costly, complicated,dangerous, and/or required extensive re-design of existing conventionalpumping equipment.

Thus, there is a present day need in the industry for an automaticallyoperating, shutoff system for use with conventional pumping apparatus toprovide for automatic gasoline flow cutoff at a predetermined dollar orvolume amount less than that required to fill a gas tank.

SUMMARY OF THE INVENTION It is an important object of this invention toprovide an efficient system for automatically interrupting fluid flowfrom a pump nozzle when, or shortly before, a predetermined dollar orvolume amount of fluid has been dispensed.

Other objects include the provision of such a system which is relativelylow in cost and can be easily installed on a wide variety of presentlyexisting gasoline pumping apparatus, which is extremely uncomplicatedand highly reliable in operation, and which does not require electricalcircuitry.

According to the invention, a system is provided for attachment to apumping apparatus which has a flow metering mechanism such as aconventional computer, and a conventional hose nozzle having anautomatic vacuum actuated full tank shutoff. The system has first meansfor supplying a predetermined volume of air at either low positivepressure or at negative pressure (with respect to atmospheric) totheautomatic hose nozzle to actuate the valve shutoff when substantiallya predetermined amount of fluid has been pumped through the nozzle. Amechanical selector means is operatively linked to the conventionalmetering mechanism for actuating the first means at any one of a numberof predetermined values in response to movement of the conventionalmetering mechanism. Preferably the first means comprises a pressurizedair supply interconnected with an automatic hose nozzle shutoff valve toprovide a positive air pressure pulse to the atmospheric pressure sideof the diaphragm within a conventional automatic shutoff mechanism.Preferably, the mechanical selector means comprise rotatable elementswhich can be hand set to a predetermined dollar value and thenrotationally driven with an internal source of power to actuate aninternal valve at a predetermined rotational orientation of therotatable elements (when the predetermined value is reached, or shortlytherebefore) and thereby release the air pulse which causes the nozzlevalve to close and thus stop fluid flow through the nozzle.

In the preferred embodiment, pacing means are provided in the form of aworm gear linked to the gear system of a conventional gasoline pumpdollar and cents computer and to the selector rotatable elements. Theworm rotation is proportional to the rate of fluid flow (as measured bythe computer) and thus the worm paces or permits the rotation of theselector means, as driven by its internal spring, at the proper rate.

It is a feature of this invention that conventional automatic full tankshutoff nozzles can be rapidly and inexpensively modified by addition ofa small number of parts to provide for the positive air pressureactuation of the shutoff means in the hose nozzle. In addition, themechanical selector meanscan be easily installed on existing pumps andrapidly and easily interengaged with conventional computers therein.

. The invention provides for cutting off gasoline flow at dollar volumesfrom $1 to $7 or higher if desired. Moreover, the automatic shutoffapparatus of this invention can be manually overridden if a mistake ismade in dialing in the dollar volume desired or if the customer changeshis mind. The operator can merely reset the dial, if required. Theconventional automatic full tank shutoff function is not in any wayimpaired by the addition of the apparatus of this invention and itcontinues to function as designed. The apparatus of this invention canbe easily maintained with a low frequency of repair. Installation israpid on existing conventional equipment so that such equipment is notplaced out of service for any extended period of time. A safety featureis provided which prevents transmission of force to the pump computerfrom the mechanical selector and the mechanical selector depends on thecomputer only for metering correlation while providing its ownoperational force.

In another aspect the invention features a fluid flow shutoff apparatusfor interrupting the flow of fluid in a conduit which acts in a precise,reproducible, and rapid manner much as the operation of an electricalsnapaction switch, but without requiring electrical circuitry. Theapparatus comprises a rotatable cam member which includes a cam surfaceand a first portion clutch. Means are provided for rotating the cammember and a cam follower unit is disposed adjacent the cam surface witha cam follower riding on that surface, biasing means maintaining thefollower in contact with the surface. A valve device is provided in theconduit and includes a blocking member, means biasing the blockingmember towards a position in which the conduit is blocked, movable meansoperative to overcome the biasing force thus applied, and means linkingthose movable means to the cam follower unit. A single direction clutchis also provided and comprises the first clutch portion mentioned above,a second clutch portion linked to pacing means, and a clutching memberfor coupling those clutch portions. A clutch release includes meansdisposed to engage said clutching member at a predetermined rotationalorientation of said cam member.

In the preferred form of this apparatus each of the clutch portionscomprises a cylindrical surface; the clutching member comprises a wrapspring engaging those surfaces and having a projecting tang, and theclutch release comprises a member fixed with respect to said cam memberand disposed to engage the tang at the predetermined rotationalorientation. With this structure, movement of the cam follower at apredetermined or base position on the cam surface can be employed tooperate the valve device movable means which ultimately causes theinterruption of fluid flow in the conduit. The amount of fluid permittedto flow prior to the interruption thereof is determined by the originalrotational orientation of the cam and the angle of rotation required toreach the original or base orientation. In that base orientation the camsurface and follower are operative, through the linking means, to soactivate the movable means of the valve device when the tang of the wrapspring engages the clutch release. When, in the rotation of the cammember toward the base orientation, the tang engages the clutch release,drag on the cam member (transmitted through the wrap spring clutch) willbe eliminated so that the cam member, under the influence of the meansfor rotating the same, can then snap quickly into the base position.This snap action causes the cam follower, in the critical range of thecam surface, to have a sudden and reproducible snap action which,through the means discussed above, causes the interruption of fluidflow. Without such snap action it would be extremely difficult to designand manufacture a cam surface and follower which would actuate the valvedevice at precisely the same rotational orientation of the cam duringeach usage of the device, especially where the cam member rotates at arelatively slow rate. In the preferred embodiment wherein theappropriate portion of the cam surface (which engages the cam followerin the base position of the cam member) is a detent, without such snapaction the surface of the follower which rides on the caming surfacecould teeter on the brink of the detent during the slow rotation of thecam member and actually drop into the detent at different elapsed timesin successive uses of the device. This, of course, would lead tononreproducible results and at least the occasional dispensing of morefluid than was desired.

When the cam is in the base position, the wrap spring clutch isdisengaged from both clutch portions and thus inputs to the pacing meansfrom the pumps computer are not transmitted to other elements of themechanical selector.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features, andadvantages of the invention will appear from the following descriptionof a particular preferred embodiment, taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a partially schematic view of a system in accordance with thepresent invention;

FIG. 2 is a plan view of the mechanical selector portion of the system;

FIG. 3 is a view taken at 33 of FIG. 2;

FIG. 4 is a view taken at 4-4 of FIG. 3;

FIG. 5 is a view taken at 55 of FIG. 3; and

FIG. 6 is a partially broken away side elevation of a conventionalgasoline pump nozzle (including conventional vacuum operated automaticfull tank gasoline shutoff) as modified in accordance with the presentinvention.

DESCRIPTION OF A PARTICULAR PREFERRED EMBODIMENT With reference to FIG.1, an improved system of this invention is shown for use with aconventional gasoline pumping apparatus (indicated schematically at 10)of the type commonly found at gasoline service stations. The systemcomprises a mechanical selector means 11 in accordance with thisinvention, an air pressure means 12 in accordance with this invention,and a conventional, pressure-differential (e.g., vacuum) actuated,gasoline hose nozzle 14 (including full tank shutoff) as modified inaccordance with this invention.

The hose nozzle 14 is basically any one-of a number of knownconventional automatic, gas-pressureactuated, full tank shutoff valvehose nozzles preferably of the type which are negative pressure (i. e.,vacuum) actuated. The nozzle is modified to provide for the additionalfeature of automatic shutoff at a predetermined dollar value, or shortlytherebefore. Nozzle 14 may be substantially similar to the hose nozzledescribed in US. Pat. No. 2,582,l95,'the basic structure of which isexemplified by the O.P.W. Division of Dover Corporation, Type IA hosenozzle.

Referring to FIG. 6, the automatic nozzle comprises a body casting 16having a gasoline conduit 18 extending from the gasoline pump side ofthe nozzle to the spout end 20 throughvwhich the gasoline flows. A firstbiased-closed valve closure 22 seats on an annular seat 24 to shut offgasoline flow through the conduit 18 I A lever arm 36 is pivoted on apin of a fulcrum point 38 for motion within an open-sided guard 40 andincludes a seat 42 for receiving the rounded end 27 of shaft 26. Fulcrumpoint 38 is in the form of a yoke 44 depending from a reciprocableplunger 46 disposed for sliding motion in a cylindrical recess 48 inbody casting 16. The plunger 46, as is known in the art, is urged to theposition shown in FIG. 6 by an upper spring 50 against the counter ofthe bias of a lower spring 52. A series of balls 54 (as described in US.Pat. No. 2,582,195) lock the plunger in the position shown in FIG. 6. Animpervious flexible diaphragm 56 is clamped in an internal recess of thebody casting 16 to define chambers 58, 60 on its opposite sides. Vacuumchamber 58 is provided with a vacuum passageway 62 leading to the outletend 20 of spout assembly 64 and also communicates with the gasolineconduit 18 in the area 66 where the spout assembly 64 connects to thebody casting 16. The chamber 60 is open to the atmosphere through asmall amount of air leakage around the plunger 46.

In the operation of such a conventional unit, the lever 36 can bepivoted about point 38 in the counterclockwise direction (as viewed inFIG. 6) so as to engage the rounded end 27 of shaft 26 in the seat 42 toapply force against the closure 22 and thereby overcome the influence ofbiasing spring 30. Such rotation of the lever 36 thus opens the valvepermitting the flow of gasoline through the conduit 18 past the valveand eventually out of the spout end 20 of the nozzle unit 14. As is wellknown, the free end 67 of lever 36 may be engaged with a conventionalholding clip 68 to maintain the valve closure 22 in an open position.With the lever 36 thus engaged with the clip 68, the flow of gasolinecan still be stopped manually by raising the lever to release its end 67from the clip 68 and then releasing the lever to allow the spring toonce again force the valve closure 22 against the valve seat 24.

The conventional full tank automatic shutoff operates, as is well knownin the art, when the gasoline in the automobiles gas tank reaches alevel to cover the opening of the vacuum passageway 62 at the end 20 ofthe spout assembly 64. At that point in time the flow of gasoline pastthe area 66 causes a drop in pressure in the chamber 58. The diaphragm56 is thus drawn upwardly and with it pin 70 to which it isattached. Pin70 extends into the plunger 46 and includes a tapered portion at alocation slightly below the balls 54. As the pin is raised to a positionwhere the tapered portion is adjacent the balls, the plunger 54 is nolonger restrained by the wcdging of the balls between the pin 70 andsurfaces on the plunger and is free to move downwardly (as viewed inFIG. 6) under the influence of spring 30 overcoming the force of spring52. The yoke 44 and the fulcrum point 38 thus also move downwardly. Thisshifting of the fulcrum point, as is well known, in conjunction with theshape and location of the holding clip 68 causes the lever 36 todisengagefrom the holding clip 68 thus freeing the lever 36 and allowingthe return of valve closure 22 to a position of sealing contact withvalve seat 24 under the influence of spring 30.

In accordance with the present invention, the conventional structure asrecited above, is modified to provide an air passageway to the chamber60. This is accomplished by the connection of flexible air tube 72withtube element 74 concentric with conduit 18. Element 74 exits valvehandle 16 and provides air passage into adapter block 76 (see FIG. 1)which forms a sealed air passage along the external surface of valvebody casting 16 to a hole communicating with chamber 60.

The tube 72 extends through the conventional flexible hose 100 extendingbetween the nozzle 14 and the pumping system 77 of a conventionalgasoline station pump (see FIG. 1).

From the above construction, it will be understood that when a pulse ofpositive pressure air is passed through the tubes 72 and 74 to thechamber 60, the diaphragm 56 moves upwardly releasing the plunger 46 andallowing it to move downwardly (under the influence of spring 30)displacing the fulcrum point 38 with the consequences as discussedabove. This structure does not in any way disturb thenormalvacuumoperated full tank shutoff feature of the nozzle. With aconventional construction of diaphragm 56, once a positive pressure of,for example, 5 psi. is built ,up in the chamber 60, and the fulcrumpoint 38 is lowered to cause automatic shutoff. The positive airpressure bleeds out between the unsealed recess 48 and the plunger 46allowing the plunger to move the fulcrum point to its normal restposition shown in FIG. 6.

The modification of the conventional nozzle as described above, iscomparatively simple to carry out with a small number of special partsneeded, all of which parts are relatively inexpensive. Moreover, thereis no disruption of the normal functions of the nozzle to provideautomatic full tank shutoff even though the system has been set for aspecific dollar amount. If the tank fills prior to that dollar amount,the nozzle will still interrupt gasoline flow.

Turning now to FIG. 1, the air pressure supply means 12 is preferablydisposed within the conventional pump casing 10 at the service island ofa gasoline service station. The means 12 include a supply tank orreservoir which, for example, has a volume of cubic inches and containsa supply of compressed air at 100 psi. A connector 91 may be provided onthe external surface of the pump casing 10 through which the tank 90 maybe replenished from, the external source of An air pulse supplied fromthe valve 94 is passed by the fitting 98 to the air tube 72 disposedwithin the flexible hose 100. The valve 94 is controlled by themechanical selector 11 (as further described below) such that, whilegasoline is flowing through the nozzle 14, the regulator 92 is connectedto the tank 96 in order to accumulate a predetermined volume of positivepressure air within tank 96 and, when the appropriate volume of gasolinehas been dispensed and shutoff is required, valve 94 connects the tank96 to the fitting 98 thereby supplying a pulse of positive pressure airto the tube 72. (Alternatively, the tank 96 could be used alone andconnected to a vacuum pump which would operate only as gasoline wasbeing pumped. The adapter block 76 wouldthen have to communicate withchamber 58. When shutoff was required, a valve would interconnect thetank 96 and the tube 72.) I

'The construction of the mechanical selector 11 and its interaction withthe two-way valve 94 may be described to FIGS. 2-5. The selector 11comprises a base 102 secured to the gasoline pump housing 10 by screws104 and a cover 106 which encloses the working parts of the selector andwhich is secured to the base by screws 108. The valve 94 is mounted onthe base 102 and openings 103, are cut in the base 102 and housing 10 topermit the'passage of air lines 110 from the interior of the housing 10.The two states of the two-way valve 94 are determined by the position ofa valve stem 112 (see FIG. 5). The valve stem is, in turn, engaged by anactuator arm 114 pivoted at 116 and including a bearing 118 which rideson a generally cylindrical outer cam surface 120 of cam 122. A detent124 (see FIG. 5) in that surface is provided and the surface 120 anddetent 124 combine to provide two positions for the actuator arm 114and, consequently, the valve stem 112. As best seen in FIG. 3, the cam122 is secured to a central shaft 126 by a pin 128. The shaft 126 7rotates in upper and lower bushings 130, 132 respectively.

A drive spring 134 is disposed in a well 136 which is integral with base102 and is secured at opposite ends to the well 136 and cam 122. A dial138 is secured by means of screw 140 to the portion of shaft 126 whichprojects above the cover 106. The dial includes a series of fingeropenings 142 and appropriate dollar amounts may be indicated on thesurface of the dial adjacent each opening or on the surface of the cover106 beneath each opening when the dial is in its rest position (theposition in FIG. 2). A conventional finger stop 144 is mounted on thecover 106 and overlies the dial 138 at the radial distance of the fingerholes from the center of the dial 138.

The selector 11 includes a first, single-direction clutch whichcomprises a wrap spring 146 which is disposed around a pair ofcylindrical surfaces. The first cylindrical surface is provided by anupward extension 148 of the hub portion of cam 122 and the secondcylindrical surface is provided by a lower extension 150 of the hubportion of a member 152 which, as will be seen below, is itself a clutchbody of a second clutch. With respect to the inner diameter of the wrapspring 146 in its relaxed state, the member 148 has an outer diameter0.007 inch more than that diameter and the member 150 has an outerdiameter 0.004 inch more than that diameter. At its lower end spring 146projects radially from the member 148 and is provided with a downwardlyprojecting tang 154 which projects through an opening 156 in the cam122. An upstanding clutch release member 158 is integral with a springcover 160 mounted on well 136. The clutch release 158 is disposed thesame radial distance from the shaft 126 keyed to a shaft 174 which issupported on portions of base 102. Also keyed to shaft 174 is a sprocket176 which engages a chain 178. At its opposite end the 'chain is trainedabout a sprocket (not shown) in the gear train between the gasoline pumpcomputer and the dollar (or gallon) indicator wheels. The chain alsoengages idler 177 (see FIG. 4) which is slidably maintained in slot 179on base 102 for adjusting tension in the chain.

As best seen in FIG. 5, the spring cover 160 has a notch 180 cut intoits periphery adjacent the clutch release 158. Indicia 182 are providedon the upper sur-.

face of the wall of well 136 and are visable in the region of the notch180. As will be discussed below, the notch 180 and indicia 182 assist inthe final calibration of the unit.

The operation of the mechanical selector is as follows. When theappropriate dollar amount is dialed in using the dial 138 and fingerstop 144, energy is stored in the drive spring 134 since its oppositeends are affixed to the stationary well 136 and the cam 122, the latteritself keyed to the shaft 126. The worm 172 is effectively locked to thegear train between the pump computer and indicator wheels by the chain178. When the attendant rotates the nozzle lever 36 and engages it withthe holding clip 68, the valve closure 22 is lifted from the seat 24 andthe flow of gasoline which results causes the operation of the computerand hence rotation of the worm 72. The worm thus paces the rotation ofthe Worm gear 164 and permits the rotation of cam 122 at a speeddetermined by the pump computer in response to the rateof gasoline flow.The force causing this rotation is actually supplied by the drive spring134. With this arrangement, excessive strain on the typically delicatecomputer mechanism is avoided.

When the appropriate dollar amount is dialed in the rotation of cam 122causes the bearing 118 to ride up out of the detent 124 and onto thecylindrical surface 120. Asa result, the valve stem 112 of two-way valve94 is depressed. With the valve stem so depresed, the valve 94 is in astate that transmits air at 30 psi. from the regulator 92 (see FIG. 1)to the one-shot holding tank 96. As the cam 122 rotates back to itsoriginal orientation and the bearing 118 drops again into detent 124,the internal connections in the valve '94 will be changed and the tank96 will be connected to the fitting 98 disposed in the flexiblevgasoline hose so that a pulse of air will be delivered through the airtube 72 to the chamber 60 (see FIG. 6) in the nozzle with the resultantre-seating of the valve closure 22 on the valve seat 24, as describedabove.

The clutch release tang 154 must be reset to a repeatable location withrespect to cam 122 when dialing in. This is accomplished by dimensioningprojection 148 slightly smaller than projection 150. On dialing intherefore wrap spring 146 will slip on projection 148 until tang 154 ispicked up by an end wall of slot 156. At this point slip will occurbetween the wrap spring clutch and projection up to the point of theoperators finger engaging the finger stop.

The slip clutch provided at interface 162 protects the sensitivecomputer against the transmission of excessive force through the worm.172, sprocket 176, and

chain 178 to the computer. Furthermore, it permits manual override sothat once a particular dollar amount has been dialed in, the operatorcan simply dial it out again and assume manual control of the fillingoperation. This would be advantageous in a number of circumstances, ofcourse, including where the operator incorrectly dialed or where thecustomer decided to change its order after filling had commenced.

The retainer clip 169, wafer 168, and wave spring washer bear-down uponthe worm gear 164 so that there is a suitable friction at the clutchinterface 162. The keys 166 which rotationally lock the wafer 168 to theclutch body 152 guarantee that any slippage will occur at the clutchinterface 162 and not at the retainer clip 169 which would degraderapidly.

The single-direction, wrap spring clutch transmits the rotational forcefrom the driven cam 122 to the clutch member 152. When, during therotation of the cam 122, the spring tang 154 strikes the clutch release158, the compressional force of the wrap spring 146 is lessened. Sincethe portion 148 of cam 122 has a smaller outer diameter than the portion150 ofv clutch body 152, the wrap spring 146 will disengage first fromthe cam. Thus, as the tang 154 engages the clutch release 158 and thecam 122 is thereby disengaged from the member 152 (and thus from thespacing effect of the worm 172), the force of the drive spring 134 willcause a very rapid rotation of the clutch 122 causing the bearing 118 toseat almost instantaneously in the detent 124. As the bearing 118 dropsinto detent 124, of course, the valve 94 is switched to its alternativeinternal connection and the pulse of air is delivered to the nozzle withthe consequent interruption of the flow of gasoline. The action of thewrap spring clutch, the cam, and the clutch release, therefore, isanalagous to an electrical snap action switch.

From the foregoing, it will be seen that the precise rotationalorientation of the clutch release 158 is important to assure theinterruption of gasoline flow at the appropriate point in the dispensingof a predetermined amount. Typically, it is desirable to interrupt theflow of gasoline a few cents (e.g., less than 10 cents) before thedollar amount has been reached. This allows the service stationattendant to top off the order to precisely the dollar amount requested.The notch 180 in spring cover 160 and the indicia 182 assist in properlylocating the correct rotational orientation of the clutch release 158.If, after initial installation, it is found that the gasoline flow isbeing interrupted somewhat too soon or somewhat too late for any givendollar amount of gasoline dialed in, the spring cover 116 may be rotatedwith respect to the well 136 (by means of arcuate slots 184 in earsl86;see (FIG. 5) by a known amount, using the indicia 182 as a guide, toattain the correct shutoff point.

From the foregoing it will be seen that a metering in fluid shutoffdevice is provided which is economical to manufacture and install,rugged in construction, and compatable with the existing gasoline pumpswith a minimum of modification. Without requiring any electricalcircuitry and employing only compressed air (commonly available atservice stations) a specific dollar amount of gasoline (or, in othercircumstances, other fluids) can be dispensed without requiring theconstant attention of the pump operator. Furthermore, a snap actionaction is achieved which assures the rapid and accurate interruption ofthe flow at a reproducible dollar volume of fuiid dependent upon thelocation of the adjustable clutch release 158. Absent the,

novel features which achieve this snap action arrangement, therelativelyslow rotation of the cam 122 and the spherical shape of the bearing 118would make the exact point of gasoline shutoff, as the bearing 118 easesinto the detent 124, indeterminant. Furthermore, shutoff may not occurat all. Slow actuation of the threeway valve 94 would result in agradual discharge of the air in the one shot tank 96. Thus, the airpressure on the diaphragm 56 in the automatic shutoff nozzle 14 maynever reach a sufficient pressure level to trip the valve.

While a particular preferred embodiment of the invention has beendescribed in detail and shown in the accompanying drawings, otherembodiments are within the scope of the invention and the followingclaims.

I claim:

1. A system for use with a fluid dispensing apparatus having a fluidflow metering mechanism and a nozzle including an automatic pressuredifferential-actuated full tank shutoff, the system comprising a holdingtank, means for maintaining the pressure in said tank at a differentialwith respect to atmospheric pressure and for connecting said holdingtank to said nozzle for actuation of said shutoff, and mechanicalselector means operatively linked to said metering system and to saidfirst mentioned means for actuating the same when substantially apredetermined amount of fluid has been dispensed through said nozzle.

2. A system for use with a fluid dispensing apparatus having a fluidflow metering mechanism and a nozzle including an automatic pressuredifferential-actuated full tank shutoff, the system comprising firstmeans for supplying a predetermined volume of positive pressure air tosaid nozzle to actuate said shutoff and mechanical selector meansoperatively linked to said metering mechanism and to said first meansfor actuating said first means when substantially a predetermined amountof fluid has been dispensed through said nozzle.

2. A system for use with a fluid dispensing apparatus having a fluidflow metering mechanism and a nozzle including an automatic pressuredifferential-actuated full tank shutoff, the system comprising firstmeans for supplying a predetermined volume of positive pressure air tosaid nozzle to actuate said shutoff and mechanical selector meansoperatively linked to said metering mechanism and to said first meansfor actuating said first means when substantially a predetermined amountof fluid has been dispensed through said nozzle, said first meanscomprising a compressed air reservoir, a holding tank for accumulatingsaid predetermined volume of positive pressure air, conduit meansintercon necting said reservoir and said holding tank and alsointerconnecting said holding tank and said nozzle, and valve meansdisposed in said conduit means operative to interconnect said reservoirand said holding tank prior to said actuation by said mechanicalselector means and to disconnect said reservoir from said holding tankand connect said holding tank to said nozzle upon said actuation by saidmechanical selector means.

3. The system as claimed in claim 2 further including regulator means insaid conduit means between said reservoir and said valve means.

4. The system as claimed in claim 3 wherein said fluid dispensingapparatus is a conventional gasoline pump and said reservoir comprises acompressed air tank disposed within the gasoline pump housing, saidsystem further including a reservoir filling connector mounted on saidhousing to project externally therefrom and additional conduit meansextending between said connector and said reservoir tank.

5. The system as claimed in claim 2, wherein said fluid dispensingapparatus comprises a conventional gasoline pump including a flexiblegasoline hose to which said nozzle is connected, said conduit meanscomprising tubing extending between said valve means and said nozzle, atleast a portion of said tubing being flexible and disposedwithinsaid-flexible hose.

6. A system for use with a fluid dispensing apparatus having a fluidflow metering mechanism and a nozzle including an automatic pressuredifferential-actuated full tank shutoff, the system comprising firstmeans for supplying a predetermined volume of positive pressure air tosaid nozzle to actuate said shutoff and mechanical selector meansoperatively linked to said metering mechanism and to said first meansfor actuating said first means when substantially a predetermined amountof fluid has been dispensed through said nozzle, said mechanicalselector means comprising an internal source of power for rotatingportions of said selector means as fluid is being dispensed and pacingmeans for limiting the rate of said rotation to an amount dependant uponthe rate at which fluid is being dispensed.

7. The system as claimed in claim 6 wherein said source of powercomprises a spiral spring secured at one end to fixed portions of saidselector means and at the other end to rotatable portions of saidselector means.

8. The system as claimed in claim 7 wherein said pacing means comprise aworm gear operatively connected to said spiral spring for rotation aboutan axis in a predetermined sense, a worm engaged with said worm gear,and means limiting the rate of rotation of said worm to a valuedependent upon the rate of flow of said fluid.

9. The system as claimed in claim 6 wherein said mechanical selectormeans comprise rotatable elements and stationary elements, saidrotatable elements in cluding a cam member driven by said internalsource of power, said cam member being linked to said pacing means by asingle direction clutch.

10. The system as claimed in claim 9 wherein said single directionclutch comprises a wrap spring clutch including a wrap spring and a pairof cylindrical clutch surfaces, one of said cylindrical clutch surfacesbeing secured for rotation with said cam member, said one of saidsurfaces of a smaller diameter than said other surface.

11. The system as claimed in claim 10 wherein a slip clutch is providedbetween said pacing means and said single direction clutch.

12. The system as claimed in claim 10 wherein said wrap spring includesa projecting tang, said system also including a clutch release,comprising a fixed member mounted to engage said tang at a predeterminedrotational orientation of said tang.

13. The system as claimed in claim 12 wherein said first means comprisea compressed air reservoir, a holding tank for accumulating saidpredetermined volume of positive pressure air, conduit meansinterconnecting said reservoir and said holding tank and alsointerconnecting said holding tank and said nozzle, and valve meansdisposed in said conduit means operative to interconnect said reservoirand said holding tank prior to said actuation by said mechanicalselector means and to disconnect said reservoir from said holding tankand connect said holding tank to said nozzle upon said actuation by saidmechanical selector means.

14. The system as claimed in claim 13 further including regulator meansin said conduit means between said reservoir and said valve means.

15. The system as claimed in claim 14 wherein said fluid dispensingapparatus is a conventional gasoline pump and said reservoir comprises acompressed air tank disposed within the gasoline pump housing, saidsystem further including a reservoir filling connector mounted on saidhousing to project externally therefrom and additional conduit meansextending between said connector and said reservoir tank.

16. Fluid flow shutoff apparatus for interrupting the flow of fluid in aconduit comprising a rotatable cam member including a cam surface,

a first clutch portion, secured to said cam member for rotationtherewith,

drive means for rotating said cam member,

a cam follower unit including a member for contact with said cam surfaceand biasing means for maintaining said member in contact with saidsurface,

a valve device in said conduit including a conduit blocking member,means biasing said blocking member toward a position in which saidconduit is blocked, movable means operative to overcome the biasingforce thus applied, and means linking said movable means to said camfollower unit,

a single direction clutch comprising said first clutch portion, arotatable second clutch portion linked to pacing means which pace therotation of said cam member under the influence of said drive means, andclutching member for selectively coupling said clutch portions, and

a clutch release comprising means disposed to engage said clutchingmember at apredetermined rotational-orientation of said cam member so asto uncouple said clutch portions, whereby said cam member is disengagedfrom said pacing means.

17. Apparatus as claimed in claim 16 wherein each of said clutchportions comprises a cylindrical surface, said clutching membercomprises a wrap spring engaging said surfaces and having a projectingtang, and said clutch release comprises a member fixed with respect tosaid cam member and disposed to engage said tang at said predeterminedrotational orientation.

18. In a gasoline pump hose nozzle having a biasedclosed dispensingvalve, a dispensing lever for opening said valve, holder means forretaining said lever such that said valve is open, a diaphragm definingfirst and second air chambers, means comprising first gas passage meansfor sensing a full gasoline tank condition and for creating a reducedpressure in said first chamber in response thereto to move saiddiaphragm, and means responsive to movement of said diaphragm todisengage said handle from said holder means thereby closing saiddispensing valve, the improvement comprising additional gas passagemeans opening into one of said chambers, whereby gas at a pressuredifferential with respect to atmospheric pressure may be introduced intosaid one of said chambers prior to said full tank condition.

19. The improvement of claim 18 further comprising a source of gas underpressure higher than atmospheric interconnected with said gas passagemeans, said gas passage means opening into said second chamber.

20. The improvement of claim 19 wherein said source of gas underpressure comprises a first holding tank having a predetermined volume ofcompressed gas sufficient to move said diaphragm, and means forinterconnecting said tank with said gas passageway when a predeterminedamount of gasoline has been pumped.

, UMTED STATES PATENT' OFFICE v CEBTEFECATE OFF CUREEUEKGN Ptent3,823,751 I Dated July 16, 197 4 Inventor(s) James I eaIy It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 7, line 57 change "wall" to ---walls--.,

Column 8, line #8 change "it s" as --his--..

Column 9, line 27 delete che parenthesis before (Fig. 5).

Column 9, line 42 change '.'fuiid" to- -fluidr' Column 10-,'lines's-lude ete claim'2.

Signed and sealed this 3rd day of December 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. 0. MARSHALL DANN Attesting Officer Commissioner ofPatents

1. A system for use with a fluid dispensing apparatus having a fluidflow metering mechanism and a nozzle including an automatic pressuredifferential-actuated full tank shutoff, the system comprising a holdingtank, means for maintaining the pressure in said tank at a differentialwith respect to atmospheric pressure and for connecting said holdingtank to said nozzle for actuation of said shutoff, and mechanicalselector means operatively linked to said metering system and to saidfirst mentioned means for actuating the same when substantially apredetermined amount of fluid has been dispensed through said nozzle. 2.A system for use with a fluid dispensing apparatus having a fluid flowmetering mechanism and a nozzle including an automatic pressuredifferential-actuated full tank shutoff, the system comprising firstmeans for supplying a predetermined volume of positive pressure air tosaid nozzle to actuate said shutoff and mechanical selector meansoperatively linked to said metering mechanism and to said first meansfor actuating said first means when substantially a predetermined amountof fluid has been dispensed through said nozzle, said first meanscomprising a compressed air reservoir, a holding tank for accumulatingsaid predetermined volume of positive pressure air, conduit meansinterconnecting said reservoir and said holding tank and alsointerconnecting said holding tank and said nozzle, and valve meansdisposed in said conduit means operative to interconnect said reservoirand said holding tank prior to said actuation by said mechanicalselector means and to disconnect said reservoir from said holding tankand connect said holding tank to said nozzle upon said actuation by saidmechanical selector means.
 3. The system as claimed in claim 2 furtherincluding regulator means in said conduit means between said reservoirand said valve means.
 4. The system as claimed in claim 3 wherein saidfluid dispensing apparatus is a conventional gasoline pump and saidreservoir comprises a compressed air tank disposed within the gasolinepump housing, said system further including a reservoir fillingconnector mounted on said housing to project externally therefrom andadditional conduit means extending between said connector and saidreservoir tank.
 5. The system as claimed in claim 2, wherein said fluiddispensing apparatus comprises a conventional gasoline pump including aflexible gasoline hose to which said nozzle is connected, said conduitmeans comprising tubing extending between said valve means and saidnozzle, at least a portion of said tubing being flexible and disposedwithin said flexible hose.
 6. A system for use with a fluid dispensingapparatus having a fluid flow metering mechanism and a nozzle includingan automatic pressure differential-actuated full tank shutoff, thesystem comprising first means for supplying a predetermined volume ofpositive pressure air to said nozzle to actuate said shutoff andmechanical selector means operatively linked to said metering mechanismand to said first means for actuating said first means whensubstantially a predetermined amount of fluid has been dispensed throughsaid nozzle, said mechanical selector means comprising an internalsource of power for rotating portions of said selector means as fluid isbeing dispensed and pacing means for limiting the rate of said rotationto an amount dependant upon the rate at which fluid is being dispensed.7. The system as claimed in claim 6 wherein said source of powercomprises a spiral spring secured at one end to fixed portions of saidselector means and at the other end to rotatable portions of saidselector means.
 8. The system as claimed in claim 7 wherein said pacingmeans comprise a worm gear operatively connected to said spiral springfor rotation about an axis in a predetermined sense, a worm engaged withsaid worm gear, and means limiting the rate of rotation of said worm toa value dependent upon the rate of flow of said fluid.
 9. The system asclaimed in claim 6 wherein said mechanical selector means compriserotatable elements and stationary elements, said rotatable elementsincluding a cam member driven by said internal source of power, said cammember being linked to said Pacing means by a single direction clutch.10. The system as claimed in claim 9 wherein said single directionclutch comprises a wrap spring clutch including a wrap spring and a pairof cylindrical clutch surfaces, one of said cylindrical clutch surfacesbeing secured for rotation with said cam member, said one of saidsurfaces of a smaller diameter than said other surface.
 11. The systemas claimed in claim 10 wherein a slip clutch is provided between saidpacing means and said single direction clutch.
 12. The system as claimedin claim 10 wherein said wrap spring includes a projecting tang, saidsystem also including a clutch release comprising a fixed member mountedto engage said tang at a predetermined rotational orientation of saidtang.
 13. The system as claimed in claim 12 wherein said first meanscomprise a compressed air reservoir, a holding tank for accumulatingsaid predetermined volume of positive pressure air, conduit meansinterconnecting said reservoir and said holding tank and alsointerconnecting said holding tank and said nozzle, and valve meansdisposed in said conduit means operative to interconnect said reservoirand said holding tank prior to said actuation by said mechanicalselector means and to disconnect said reservoir from said holding tankand connect said holding tank to said nozzle upon said actuation by saidmechanical selector means.
 14. The system as claimed in claim 13 furtherincluding regulator means in said conduit means between said reservoirand said valve means.
 15. The system as claimed in claim 14 wherein saidfluid dispensing apparatus is a conventional gasoline pump and saidreservoir comprises a compressed air tank disposed within the gasolinepump housing, said system further including a reservoir fillingconnector mounted on said housing to project externally therefrom andadditional conduit means extending between said connector and saidreservoir tank.
 16. Fluid flow shutoff apparatus for interrupting theflow of fluid in a conduit comprising a rotatable cam member including acam surface, a first clutch portion, secured to said cam member forrotation therewith, drive means for rotating said cam member, a camfollower unit including a member for contact with said cam surface andbiasing means for maintaining said member in contact with said surface,a valve device in said conduit including a conduit blocking member,means biasing said blocking member toward a position in which saidconduit is blocked, movable means operative to overcome the biasingforce thus applied, and means linking said movable means to said camfollower unit, a single direction clutch comprising said first clutchportion, a rotatable second clutch portion linked to pacing means whichpace the rotation of said cam member under the influence of said drivemeans, and clutching member for selectively coupling said clutchportions, and a clutch release comprising means disposed to engage saidclutching member at a predetermined rotational orientation of said cammember so as to uncouple said clutch portions, whereby said cam memberis disengaged from said pacing means.
 17. Apparatus as claimed in claim16 wherein each of said clutch portions comprises a cylindrical surface,said clutching member comprises a wrap spring engaging said surfaces andhaving a projecting tang, and said clutch release comprises a memberfixed with respect to said cam member and disposed to engage said tangat said predetermined rotational orientation.
 18. In a gasoline pumphose nozzle having a biased-closed dispensing valve, a dispensing leverfor opening said valve, holder means for retaining said lever such thatsaid valve is open, a diaphragm defining first and second air chambers,means comprising first gas passage means for sensing a full gasolinetank condition and for creating a reduced pressure in said first chamberin response thereto to move said diaphragm, and means responsive tomovement of said diaphragm to disengage said handle from said holdermeans thereby closing said dispensing valve, the improvement comprisingadditional gas passage means opening into one of said chambers, wherebygas at a pressure differential with respect to atmospheric pressure maybe introduced into said one of said chambers prior to said full tankcondition.
 19. The improvement of claim 18 further comprising a sourceof gas under pressure higher than atmospheric interconnected with saidgas passage means, said gas passage means opening into said secondchamber.
 20. The improvement of claim 19 wherein said source of gasunder pressure comprises a first holding tank having a predeterminedvolume of compressed gas sufficient to move said diaphragm, and meansfor interconnecting said tank with said gas passageway when apredetermined amount of gasoline has been pumped.